shim-cli started with a question we couldn t answer: what does a coding agent actually send to the model? When Claude Code reads a .env or a customer CSV to debug something, the contents go straight into the request, and you never see that step.
So we built two things. In Claude Code, a local hook masks secrets and personal data in tool results before the model reads them. shim watch shows what a session sent and what it cost. Everything runs on your machine: no account, no telemetry. It s open source (Apache-2.0).
We launch here on October 18. Until then we ll post one short thread a day on how it works and where it falls short.
An open-source hook and local proxy for Claude Code, Codex, Copilot CLI and VS Code. In Claude Code it masks secrets and personal data in tool results before the model reads them, and shim watch shows what a session sent and cost. No account, no telemetry.
